The overall aims of our research program are two-fold. One of these is the understanding of the electronic structures of the constituents of the reaction centers in the photosynthetic apparatus of bacterial systems and chloroplasts with emphasis on the former ad the other is the understanding of the mechanisms of electron transfer between various units in the reaction centers. The major directions of our efforts last year, represented by the first three titles of the attached list involving papers under preparation or in course of publication, are : (a) the investigation of electron distributions over the anion of the ubiquinone in the primary acceptor system of the reaction center and testing of this by comparison with recent proton hyperfine interaction data, (b) the analysis of mechanisms that can contribute to the zero-field splitting of electron paramagnetic resonance signals in triplet states of bacteriochlorophyll and chlorophyll and monomers and the Ubiquinone-Fe plus 2 ion complex and the test of procedures for the evaluation of these contributions by application to simple ionic systems and (C) the anlysis of various sources of contributions to the nuclear quadrupole interaction of 25Mg nucleus in chlorophyll and bacteriochlorophyll monomers including antishielding effects and test fo procedures for the evaluation of these contributions by application to Al203. Our efforts over the next year will be channelled in five directions: (a) improved understanding of the electron distribution on the anion state of Ubiquinone in the primary acceptor in bacterial reaction cetner, (b) the nature of the interaction between the Fe ion 2 ion and Ubiquinone anion, (c) the understanding of the zerofield splitting and interstate crossing parameters D, E and ki in the triplet states of chlorophyll and bacteriochlorophyll systems, (d) the origin of nuclear quadrupole interactions for 25Mg, III Cd and 14N nuclei in chlorophyll, bacteriochlorophyll and related systems and (e) the mechanisms of tunneling of the unpaired electrons between the monomer units of the cation state of the primary donor and between the primary acceptor and the other Ubiquinone in the bacterial reaction center.